You mentioned about reducing the light, which is good esp for discus; floating plants also help to calm them. Your plants with the exception of the stem plants are fairly low-medium light. But you are dosing with CO2, and that means light has to balance or the CO2 is wasted (along with the other nutrient fertilizers). Plants can only use all this if it is balanced; we term it the limiting factor, which should always be light (to avoid algae issues) but reducing the light means there is then no need for the nutrients in such large amounts relatively speaking.

Some swords wold suit the discus, I mentioned some previously in this thread. Discus and angels occur in much the same type of habitat. But the two should never be combined in the same aquarium.

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.[unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

I will remove the angelfish to put in the discus.
I will not dose ferts since not needed.
I will remove Rotala Indica and get a crypt.
Light will be reduced to 6 hours.
My main water has a ph of 8 so I use the CO2 purely to get ph 6.5 (is this good?)

I will remove the angelfish to put in the discus.
I will not dose ferts since not needed.
I will remove Rotala Indica and get a crypt.
Light will be reduced to 6 hours.
My main water has a ph of 8 so I use the CO2 purely to get ph 6.5 (is this good?)

Any issues i might encounter?

thanks as always byron

You will still need some fertilization, whatever the light level. And with CO2 even more or other issues will develop (like algae). If the CO2 stays (and the pH is an issue for this), reducing the duration and getting lots of floating plants to basically cover the surface will work. The crypts manage on low light when shaded.

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.[unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]